Hybrid design makes Geothermal HVAC Affordable

Hybrid design makes Geothermal HVAC Affordable

This article was original published for the Talkin’ Green column. Download a copy of the column from the Lake Geneva Regional News Real Estate Guide.

Heating, cooling and the production of hot water are necessary components for the operation of most residential and commercial buildings. And according to the U.S. Department of Energy (DOE) Office of Geothermal Technologies, the operation of these components is responsible for close to 40 percent of ALL U.S. CO2 emissions. That’s a staggering number and an obvious place for change.
The answer – Geothermal Energy Systems.

The Basics

Geothermal systems harness the heat stored deep within the earth, and capture it for multiple purposes including, heating and cooling, hot water and electricity. Typically, this is done utilizing vertical closed loop wells or running piping six feet underground, horizontally.


The Environmental Protection Agency (EPA) calls geothermal ground source systems one of the best choices to make for energy efficient, environmentally clean, and cost-effective HVAC and hot water production. After all, it’s renewable energy taken right from the earth; the largest energy storage system around, with no fossil fuels involved.

So why doesn’t everyone have a geothermal system?

Up until now – the upfront cost has been prohibitive. You see, using a geothermal system, the typical home needs around three tons of air conditioning and five tons of heating. And because geothermal does heating, cooling and hot water from a single system, it is usually sized to carry the biggest load. For northern locations, that means having to oversize the entire system just to handle a few peak days of extreme temperatures. That kind of cost can really add up, putting geothermal out of reach. But the introduction of a new hybrid geothermal design can make geothermal much more affordable.

Hybrid System

A hybrid design can carry a load that is somewhere in between the requirements for hot and cold extreme temperatures. With the addition of a natural gas 92% efficient tankless water heater to serve as a booster, the hybrid system is able to meet those occasional peak winter days. This combination offers big initial cost savings in that it downsizes the geothermal system required. The overall cost savings can be from 20 to 40 percent, with the entire system still qualifying for the current 30 percent residential Federal Investment Tax Credit (ITC). For a commercial system, they only qualify for a 10% ITC, but the geothermal systems total cost can still be fully depreciated as an additional payback.

The Department of Energy and www.seventhwave.org (formerly WI Energy Center) have done numerous studies on hybrid systems in northern and southern climates. They found a significant savings in up front capital, with just a minimal loss in energy savings between a 100% geothermal system and a hybrid system. Seventhwave.org has also developed a hybrid geothermal heat pump modeling tool to see what the impact of a hybrid system would mean to upfront and operational costs across the United States.


A geothermal heat pump can save 40% to 70% off the traditional costs to heat and cool your home. There is also less maintenance since the wells are underground and the geothermal system is inside the basement or mechanical room, out of the weather, compared to your traditional air conditioning system. The geothermal system has an expected 20 year life and the closed loop geothermal wells are expected to easily last 50-60 years.

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Fritz Kreiss

Fritz has been involved in energy procurement and the field of sustainability for close to twenty years, with expertise in alternative energy development including geothermal, wind and solar farm developments.

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